A conventionally used evaporator for use in a car air conditioner includes a plurality of refrigerant flow members arranged in parallel, and corrugate fins each disposed between and brazed to the adjacent refrigerant flow members. Each of the corrugate fins includes wave crest portions, wave trough portions, and horizontal connection portions connecting together the wave crest portions and the wave trough portions. The wave crest portions and the wave trough portions are brazed to the refrigerant flow members. A plurality of louvers are formed in the connection portions in such a manner as to be juxtaposed in the air flow direction.
In the evaporator, a portion of condensed water on the surface of the refrigerant flow members and on the surface of the corrugate fins flows downward through openings between adjacent louvers. The residual condensed water flows, by the effect of surface tension, toward joint portions between the refrigerant flow members and the wave crest portions of the corrugate fins and toward joint portions between the refrigerant flow members and the wave trough portions of the corrugate fins. Then, the residual condensed water flows, by the effect of the flowing air, in the air flow direction and flows downward along the front ends of the refrigerant flow members. However, in the case where the quantity of condensed water is large, a large quantity of condensed water stagnates at the joint portions, and is not drained sufficiently from the front-end side, which raises a problem in that when the flow rate of air abruptly changes, the condensed water scatters, or the condensed water closes the clearances between louvers by means of surface tension to thereby lower cooling performance. Moreover, the condensed water may freeze.
An evaporator in which the above problem is solved has been proposed. In the evaporator, a corrugate fin disposed between adjacent flat tubes is divided into a plurality of separate fin members, which are arranged at predetermined intervals in the air flow direction. A clearance is formed between the adjacent separate fin members. Drain grooves for draining condensed water are formed on the outer surface of the flat tubes at positions corresponding to the clearances. (Such an evaporator is proposed in, for example, Japanese Patent Application Laid-Open (kokai) No. 10-141805.)
However, in the evaporator described in the above-mentioned publication, each of the corrugate fins is divided into a plurality of separate fin members, which are arranged at predetermined intervals in the air flow direction, and a clearance is formed between the adjacent separate fin members. This, in manufacture of the evaporator, raises a problem that assembling together the refrigerant flow members and the separate fin members is troublesome. Also, as compared with an undivided corrugate fin, the divided corrugate fin is smaller in the area of heat transfer with air that flows through an air-passing clearance between adjacent refrigerant flow members, thus raising a problem of an impairment in heat-exchanging performance.
An object of the present invention is to solve the above problem and to provide an evaporator which exhibits excellent drainage of condensed water and enables high work efficiency in manufacture thereof.